Adds markers to surrendering AI units

[X0-11]

The AI surrender script now creates a simple objective marker on surrendering AI to allow players to locate them easier after battles, to allow for less tedious post-battle cleanup.

As-is, finding surrendered enemies in built-up areas, forests, or any highly obstructive terrain is an exercise in boredom and transporting + corraling them back to base already provides the downtime needed for enemy attack timers and such to tick onwards.

[tbox1911]

that's the dog's job! use it to locate the last prisoners/enemies

plain marker will be too easy :)